3-D Reconstruction of the Ethmoidal Arteries of the Medial Orbital Wall Using Biodur® E12

Objectives The medial wall of the orbit is reported to contain anterior and posterior ethmoidal foramina, through which pass branches of the ophthalmic artery. These arteries are a potential source of bleeding during surgical procedures involving the medial orbital wall. However, recent research has revealed variable numbers of accessory ethmoidal foramina, which have also been shown to transmit vascular structures, making intraorbital surgery unpredictable and potentially hazardous. This study aims to elucidate the branching pattern of the arterial supply of the medial orbital wall, particularly in cases of multiple ethmoidal foramina. Materials and Methods Orbits were retrieved from cadavers donated for anatomical examination. Red silicone was injected into the ophthalmic artery via the internal carotid. The medial orbital wall was then dissected from contiguous craniofacial structures and embedded in Biodur® Epoxy E12 resin. Sections of 0.3 mm thickness were cut with a slow speed diamond saw, stained with Miller’s stain for elastin and then photographed with a digital camera. Three-dimensional reconstructions were carried out using WinSURF software. Results The optical qualities of the epoxy resin blocks were excellent, though this was not always the case with the individual sections. However, in the stained sections, the arteries were clearly visible. Using WinSURF, the outlines of the branches of the ethmoidal arteries and the bone lining the medial wall of the orbit were delineated. A three-dimensional model of the pattern of arterial branching was created. Conclusion Surgeons operating along the medial wall of the orbit need to be aware that multiple branches of the ethmoidal artery may be encountered. Three-dimensional reconstructions of the branching pattern give a clearer understanding of the blood supply to the medial wall. Work is on-going to map the variations in the branching of the ophthalmic artery.